Referring to FIG. 1, a patent foramen ovale (PFO) 2 is a flap-like opening in the wall 4 between the left atrium 6 and the right atrium 8 of the heart 10. That opening typically closes at or shortly after birth. However, in an estimated 20-25% of people, the PFO 2 remains open into adulthood. The PFO 2 allows blood clots in the bloodstream to bypass the natural filtering mechanism of the lungs, which can lead to stroke. A person with a PFO 2 is generally asymptomatic, and generally does not know he or she has a PFO 2 until after a stroke. In addition, research suggests a correlation between PFO 2 and migraine, the mechanism of which is still unknown.
Currently, patients having a known PFO 2 are treated in one of two ways. The patient may be prescribed blood thinners such as coumadin, to reduce the risk of clot formation. However, this course of treatment requires lifelong dependence on that medication, which does nothing to close the opening between the atria. Alternately, a device may be placed through the PFO 2 and then unfurled like a tent on each side of the PFO 2. Such a device may include a material such as polyester stretched over a wire frame, or stuffed inside a wire mesh. However, such devices can expose a significant amount of metal to the bloodstream, which is considered undesirable.
The use of the same reference symbols in different figures indicates similar or identical items.